Vibration Control of a High-Rise Building Structure:Theory and Experiment

In this study,an innovative solution is developed for vibration suppression of the high-rise building.The infinite dimensional system model has been presented for describing high-rise building structures which have a large inertial load with the help of the Hamilton’s principle.On the basis of this system model and with the use of the Lyapunov’s direct method,a boundary controller is proposed and the closed-loop system is uniformly bounded in the time domain.Finally,by using the Smart Structure laboratory platform which is produced by Quancer,we conduct a set of experiments and find that the designed method is resultful.

Safety analysis of optimal outriggers location in high-rise building structures

This paper presents the restraining moments of outriggers acting on the core wall and the equation of the horizontal top deflection based on a simplified outrigger model. The deformation compatibility conditions between outriggers and core wall as well as the finite rigidities of outriggers are also considered. One case study was carried out to analyze the horizontal top deflection and the mutation of the restraining moments caused by the variation of outrigger location. The results showed that the method adopted in the paper is simple and reasonable. Some conclusions are valuable to the safety design of high-rise building structures.

Experimental investigation of turbulent flows around high-rise structure foundations and implications on scour

Many studies have been undertaken to predict local scour around offshore high-rise structure foundations(HRSFs),which have been used in constructing the Donghai Wind Farm in China.However,there have been few works on the turbulent flow that drives the scour process.In this study,the characteristics of the turbulent flow fields around an HRSF were investigated using the particle image velocimetry technique.The mean flow,vorticity,and turbulence intensity were analyzed in detail.The relationship between the flow feature and scour development around an HRSF was elaborated.The results showed that the flow velocity increased to its maximum value near the third row of the pile group.The shear layer and wake vortices could not be fully developed downstream of the last row of the piles at small Reynolds numbers.The strong flow and turbulent fluctuation near the third piles explained the existence of a longtail scour pattern starting from the HRSF shoulders and a trapezoidal deposition region directly downstream of HRSF.This laboratory experiment gains insight into the mechanism of the turbulent flow around HRSFs and provides a rare dataset for numerical model verifications.

Research of CBR, DM and smart algorithms based design methods for high-rise building structure form-selection

First, the high-rise building structure design process is divided into three relevant steps, that is, scheme generation and creation, performance evaluation, and scheme optimization. Then with the application of relational database, the case database of high-rise structures is constructed, the structure form-selection designing methods such as the smart algorithm based on CBR, DM, FINS, NN and GA is presented, and the original forms system of this method and its general structure are given. CBR and DM are used to generate scheme candidates; FINS and NN to evaluate and optimize the scheme performance; GA to create new structure forms. Finally, the application cases are presented, whose results fit in with the real project. It proves by combining and using the expert intelligence, algorithm intelligence and machine intelligence that this method makes good use of not only the engineering project knowledge and expertise but also much deeper knowledge contained in various engineering cases. In other words, it is because the form selection has a strong background support of vast real cases that its results prove more reliable and more acceptable. So the introduction of this method provides an effective approach to improving the quality, efficiency, automatic and smart level of high-rise structures form selection design.

Discussion on Construction Technology and Welding Deformation of High-Rise Steel Frame Structure

Because of urbanization,land resources in China’s cities has become increasingly scarce.Therefore,modern buildings are becoming taller,making high-rise steel frame structures the new favorite of the construction industry.However,the construction of high-rise steel frame structures requires advanced technology.If the construction technology is effectively implemented and the welding techniques of the construction personnel align with the requirements for high-rise steel frame structures,it can help mitigate deformations in the steel structure,thus preserving the overall construction quality of high-rise steel frame structures.To enhance the applicability of steel frame structures in high-rise buildings,this paper focuses on analyzing the optimization path for the construction process of high-rise steel frame structures.It introduces a tailored approach to control welding-induced deformations in steel frame structures,aiming to make a valuable contribution to the advancement of China’s construction industry.

Discussion on seismic design of high-rise building structure in China

With the rapid development of China＇s economy, the modernization drive and the process of urbanization continue to advance, land for urban construction is becoming more and tenser and land prices are rising steadily, there are more and more high-rise buildings, its density is also increasing. With the increasing number trend of high-rise building development, anti-seismic building requirement as an important part of architectural design is worthy of our exploration and study. Seismic resistance has become an important subject of engineering design. This paper will discuss the technical principle of seismic design in building structure design, so as to optimize the seismic design of high-rise building structure better.

Dynamic analysis of wind turbine tower structures in complex ocean environment

Studying and analyzing the dynamic behavior of offshore wind turbines are of great importance to ensure the safety and improve the efficiency of such expensive equipments.In this work,a tapered beam model is proposed to investigate the dynamic response of an offshore wind turbine tower on the monopile foundation assembled with rotating blades in the complex ocean environment.Several environment factors like wind,wave,current,and soil resistance are taken into account.The proposed model is ana-lytically solved with the Galerkin method.Based on the numerical results,the effects of various structure parameters including the taper angle,the height and thickness of the tower,the depth,and the diameter and the cement filler of the monopile on the funda-mental natural frequency of the wind turbine tower system are investigated in detail.It is found that the fundamental natural frequency decreases with the increase in the taper angle and the height and thickness of the tower,and increases with the increase in the diameter of the monopile.Moreover,filling cement into the monopile can effectively im-prove the fundamental natural frequency of the wind turbine tower system,but there is a critical value of the amount of cement maximizing the property of the monopile.This research may be helpful in the design and safety evaluation of offshore wind turbines.

Equivalent Simplifying of Tower Structure and Its Application in Overall Analysis of Offshore Platform

Based on some mechanical principles, this paper presents a new way for simplifying the tower structure on the platform, i. e., substituting the three-dimensional tower structure by using beam elements. For the overall analysis of offshore platform, this method can not only save man- power and computer time, but also get better results. This paper introduces the equivalent-simplifying method and its application in engineering.

Safety Risk Assessment of Overturning Construction of Towering Structure Based on Cloud Matter–Element Coupled Model

Rapid urbanization has led to a surge in the number of towering structures,and overturning is widely used because it can better accommodate the construction of shaped structures such as variable sections.The complexity of the construction process makes the construction risk have certain randomness,so this paper proposes a cloudbased coupled matter-element model to address the ambiguity and randomness in the safety risk assessment of overturning construction of towering structures.In the pretended model,the digital eigenvalues of the cloud model are used to replace the eigenvalues in the matter–element basic element,and calculate the cloud correlation of the risk assessment metrics through the correlation algorithm of the cloud model to build the computational model.Meanwhile,the improved hierarchical analysis method based on the cloud model is used to determine the weight of the index.The comprehensive evaluation scores of the evaluation event are then obtained through the weighted average method,and the safety risk level is determined accordingly.Through empirical analysis,(1)the improved hierarchical analysis method based on the cloud model can incorporate the data of multiple decisionmakers into the calculation formula to determine theweights,which makes the assessment resultsmore credible;(2)the evaluation results of the cloud-basedmatter-element coupledmodelmethod are basically consistent with those of the other two commonly used methods,and the confidence factor is less than 0.05,indicating that the cloudbased physical element coupled model method is reasonable and practical for towering structure overturning;(3)the cloud-based coupled element model method,which confirms the reliability of risk level by performing Spearman correlation on comprehensive assessment scores,can provide more comprehensive information of instances compared with other methods,and more comprehensively reflects the fuzzy uncertainty relationship between assessment indexes,which makes the assessment results more realistic,scientific and reliable.

Structural form selection of the high-rise buildingwith the improved BP neural network

As civil engineering technology development,the structural form selection is more and more critical in design of high-rise buildings.However,structural form selection involves expertise knowledge and changes with the environment which makes the task arduous.An approach utilizing improved back propagation(BP)neural network optimized by the Levenberg-Marquardt(L-M)algorithm is proposed to extract the main controlling factors of structural form selection.Then,an intelligent expert system with artificial neural network is constructed to design high-rise buildings structure effectively.The experiment tests the model in 15 well-known architecture samples and get the prediction accuracy of 93.33%.The results show that the method is feasible and can help designers select the appropriate structural form.

The Coupling Effect of Spatial Reticulated Shell Structure with Cables

The spatial reticulated shell structure with cables (RSC) is a kind of coupling working system, which consists of flexible cables, reticulated shell structure (RS) and tower columns. The dynamic analysis of RSC based on the coupling model was carried out. Three kinds of elements such as the spatial bar element, cable element and beam element were introduced to analyze the reticulated shell, cable and tower column respectively. Furthermore, such parameter influences as structural boundary conditions, grid configuration, the span-to-depth ratio and the arrangement of cable system upon structural dynamics were analyzed. The structural vibration modes can be divided into four groups based on some numerical examples. And the frequencies in the same group are very close while the frequencies in different groups are different from each other obviously. It is clear that the sequence of the appearance of the each mode group heavily depends on the comparative stiffness of the tower column system, RS and cables.

Influence of Wind Turbine Structural Parameters on Wind Shear and Tower Shadow Effect

To overcome the problems of natural decreases in power quality,and to eliminate wind speed fluctuation due to wind shear and tower shadow effect arising from wind turbine structural parameters,an improved prediction model accounting for the dual effect of wind shear and tower shadow is,in this paper,built.Compared to the conventional prediction model,the proposed model contains a new constraint condition,which makes the disturbance term caused by the tower shadow effect always negative so that the prediction result is closer to the actual situation.Furthermore,wind turbine structural parameters such as hub height,rotor diameter,the diameter of the tower top,and rotor overhang on wind shear and tower shadow effect are also explored in detail.The results show that the wind shear effect became weaker with the increase in hub height.The hub height is independent of the tower shadow effect.The rotor diameter is positively correlated with the wind shear and tower shadow effect.The tower shadow effect is positively correlated with the diameter of the tower top and negatively correlated with the rotor overhang.

Research on ETABS Steel Tower atop Building Structural System

Equipping steel tower atop building structural system at the top of high-rise buildings is applied increasingly. However, the earthquake disasters indicate that under seismic effect, the tower on the roof reacts strongly to the earthquake, and the gazebo is damaged greatly under the condition that major structure has no earthquake damage. Based on analyzing the characteristics and application methods of ETABS software, for engineering projects, the paper uses ETABS software and simplified calculation method to calculate and make comparison analysis on steel tower atop building structure. The analysis results indicate that the method established in the paper has higher accuracy, which can meet the engineering requirements.

High-Rise Residential Reinforced Concrete Building Optimisation

In the last few decades structure optimisation has become a main task in a civil engineering project. As a matter of fact, due to the complexity and particularity of every structure, the great amount of variables and design criteria to considerate and many other factors, a general optimisation’s method is not simple to formulate. As a result, this paper focuses on how to provide a successful optimisation method for a particular building type, high-rise reinforced concrete buildings. The optimization method is based on decomposition of the main structure into substructures: floor system, vertical load resisting system, lateral load resisting system and foundation system;then each of the subsystems using the design criteria established at the building codes is improved. Due to the effect of the superstructure optimisation on the foundation system, vertical and lateral load resisting system is the last to be considered after the improvement of floor. Finally, as a case example, using the method explained in the paper, a 30-story-high high-rise residential building complex is analysed and optimised, achieving good results in terms of structural behaviour and diminishing the overall cost of the structure.

Flexible high-rise apartments with sparse wall-frame structure:A data-driven computational approach

Flexible housing resolves the fundamental conflicts between the long-standing structure and the evolving demands.We propose a computational method of optimizing the structural layout of high-rise residential buildings.Chinese high-rise apartment buildings have widely employed shear wall-frame structure in which one big room or multiple small rooms could occupy the same span.Fitting multiple floor plans into a fixed sparse scheme of shear walls and columns is feasible.We developed a computational framework to seek flexible structural schemes.A building scheme consists of a circulation core,shear walls,columns,and boundaries.The computer program automatically adapts floor plans to any drawn or generated scheme.Based on a large dataset of apartment layouts,the number of apartments that fit into a building scheme statistically reflects the flexibility of the scheme.If many hypothetical plans can fit into a wallframe structure in computer simulation,this structure could probably support several generations of unknown plans.Such a data-driven computational method provides the possibility of creating a one-to-many mapping between permanent structure and evolving apartment plans.

轻中冰区悬垂塔型式对铁塔一阶振型影响研究

轻中冰区悬垂塔的受力主要受风荷载控制,而风致效应主要受铁塔一阶振型的方向影响,一阶振型为横担方向横向振动时,符合规范等效静力荷载的计算假定,计算得到的风荷载效应最不利,反之,计算得到的风致效应并不是最不利的,可能使得设计偏于不安全,因此研究输电塔的自振特性对其受力显得十分重要。基于结构力学基本原理和数值模拟研究了悬垂塔不同结构型式下的振型特性,研究表明:悬垂塔呈鼓型布置时,由于横担较短,横担的质量占比较小,扭转效应较弱,一阶振型表现为横向振动;悬垂塔羊角型(直流双极塔)布置时,由于横担较长,横担的质量占比较大,扭转效应明显,一阶振型表现为扭转;悬垂塔为酒杯塔和猫头塔时,一阶振型主要受塔窗轮廓材的相对规格比控制;并结合参数分析结论提出了不同布置型式下保证悬垂塔一阶横向振动的措施,研究结论对工程实践具有一定的指导意义。

Research and Implementations of Structural Monitoring for Bridges and Buildings in Japan

This paper provides a review on the development of structural monitoring in Japan, with an emphasis on the type, strategy, and utilization of monitoring systems. The review focuses on bridge and building structures using vibration-based techniques. Structural monitoring systems in Japan historically started with the objective of evaluating structural responses against extreme events. In the development of structural monitoring, monitoring systems and collected data were used to verify design assumptions, update speci cations, and facilitate the ef cacy of vibration control systems. Strategies and case studies on monitoring for the design veri cation of long-span bridges and tall buildings, the performance of seismic isolation systems in building and bridges, the veri cation of structural retro t, the veri cation of structural control systems (passive, semi-active, and active), structural assessment, and damage detec- tion are described. More recently, the application of monitoring systems has been extended to facilitate ef cient operation and effective maintenance through the rationalization of risk and asset management using monitoring data. This paper also summarizes the lessons learned and feedback obtained from case studies on the structural monitoring of bridges and buildings in Japan.

The Structural Behavior of Low/Medium/High Rise Concrete Office Buildings in Kuwait

The main concern of this paper is to provide an extensive study for the structural behavior of low/medium/high rise office buildings aiming to deepen structure and architect designers understanding for such type of buildings. The study is performed on reinforced concrete and emphasized only on Kuwait city conditions for wind. Regular layout plan building with different heights ranging from five to fifty typical office stories are investigated in this study. Three dimensional finite element techniques through ETABS software are used in conducting analysis for structures presented here-in. A serviceability study is performed to ensure that buildings have sufficient stability to limit lateral drift and peak acceleration within the acceptable range of occupancy comfort. In addition, an ultimate strength study is carried out to design and verify that all the structural elements are designed to withstand factored gravity and lateral loadings in a safe manner according to the international building codes. The building slenderness ratio and the building core size and location are the studied parameters since they are the key drivers for the efficient structural design. Analysis results are presented and discussed and finally conclusions are summarized as guidelines for designers of concrete office buildings in Kuwait.

New Technology of Installing the Attached Self-Climbing Tower Steel Gantry Cranes

The Liujiaxia Bridge is 536 m span steel truss stiffening Girder Bridge, tower with double-column steel concrete slructure, which is the world＇s largest diameter, the largest steel plate thickness of concrete pylon. Sarasota manufactured using standard pipe segment, group fight scene segment piecewise hoisting tower segment perfusion within the micro-expansion concrete construction technology, tower maximum height of 61.5 meters. This paper describes a piecewise Sarasota steel installation, piecewise perfusion within the micro-expansion concrete tower new construction method - attached to a self-climbing tower bridge ganlry crane mounted pylon construction technology of large steel components. Of the ＂entity attached to the pylon installation of equipment by section climb＂ design, composition and construction applications are described in detail.

The Minaret of the Great Mosque in Algiers,a Structural Challenge

The Great Mosque in Algiers will be the third largest mosque in the world and its minaret the highest. The region has a high seismic risk. The project designed by a German team of architects and engineers is under construction and will be finished by 2016. Due to the minaret slenderness and to the special composite structure chosen to withstand lateral loading, the structural design faced some challenging aspects. The paper presents the design philosophy, some significant structural features and details of the minaret structure.